Mk3 petrol: crankcase emission vent valve

[Kjeles]

Haynes lists the crankcase emission vent valve on a Mk3 petrol as a 'service item' to be replaced every 40.000 km. However, I cannot find this part at any of my normal car part suppliers. I found one at Burton Power, UK, though.
Is this a hard-to-find item or do suppliers use different names for it?
What is your experience?

[dumper]

Not worked on transit petrol but I have on Kent OHC pinto V 6 and 2 L twincam I remember removing the tin case with the suction valve and cleaning it out but only if it had a problem on the Kent and pinto the only Ford I can remember changing a filter in the breather system was on the CVH engine was a filler that plug into the bottom of the air filter housing and piped into the crankcase and the inlet manifold on the mk3 escort we called it the Sputnik and we change them very often the latter ones had a sponge filler in the air filter box has yours got one it maybe something like that .
If you put up what engine you have someone maybe have a bit more info

[Kjeles]

Thanks.
The engines are 2.0 L OHC 202 block.
Below is a copy of a photo in the Haynes manual showing the removal of the valve from the separator.
Since the valve is a service item, I expected it to be available from online part stores.

What is the function of the vent valve?
Can it be cleaned if replacement is not available?

Figure 25.2.jpeg

[Chug]

I have only ever cleaned and replaced, never swapped one.

[DodgeRover]

Also known as a PCV valve positive crankcase ventilation.

[V184]

was changed every 24k (major svs)